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#21
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Mining the moon for unlimited Energy.
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#22
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Mining the moon for unlimited Energy.
Gordon D. Pusch wrote:
Hmph. On re-examining Rider's dissertation, it appears you are correct, and my memory of a factor of 15 was wildly wrong. Assuming quasi-neutrality, separate maxwellian distributions for ions and electrons, =NO_ energy losses except bremsstrahlung, and that =ALL= the fusion-product power can somehow be magically recycled back into heating the fuel ions and _NOT_ into heating the electrons, Rider gets: fuel | P_brem/P_fus --------+-------------- D-T | 0.007 D-He3 | 0.19 D-D | 0.35 (other fuels clipped) The separate maxwellian distributions for ions and electrons follows naturally from the energy loss via bremsstrahlung. This process draw energy from the electrons, so to balance their temperature must be lower than that of the ions. I'll also add that the P_brem/P_fus ratio for D-3He in the table assumes a 1:1 ion ratio. Increasing the fraction of D reduces the P_brem/P_fus ratio a bit (see figure 7.3 in the thesis). This also increases the neutron output, but (for the case of rapid removal of T from the plasma) it's still well below that of DT or DD plasmas. It's not clear to me that the P_brem/P_fus ratios for DT include the 80% of the fusion energy that goes into the neutrons. If this is the case, the figure is misleading, since most of the fusion energy from a fusion D-3He plasma will be in charged particles and will be immediately available for heating the plasma. The large tritium inventory in this case (waiting for all that removed tritium to decay back to 3He) is worrisome. Paul |
#24
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Mining the moon for unlimited Energy.
"Gordon D. Pusch" wrote in message
... IIRC, it pre-dates Zubrin substantially. In fact, I vaguely recall that it might even have appeared on a page or two of O'Neill's "The High Frontier"... I doubt that. O'Neill was pushing the use of lunar resources to build SPS. I think he was of the opinion that fusion was not going to make SPS obsolete in any foreseeable future. He did talk about harvesting lunar ice at the poles though, the existence of which was purely theoretical at the time. -- Regards, Mike Combs ---------------------------------------------------------------------- We should ask, critically and with appeal to the numbers, whether the best site for a growing advancing industrial society is Earth, the Moon, Mars, some other planet, or somewhere else entirely. Surprisingly, the answer will be inescapable - the best site is "somewhere else entirely." Gerard O'Neill - "The High Frontier" |
#25
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Mining the moon for unlimited Energy.
"Mike Combs" wrote in message ...
"Gordon D. Pusch" wrote in message ... IIRC, it pre-dates Zubrin substantially. In fact, I vaguely recall that it might even have appeared on a page or two of O'Neill's "The High Frontier"... I doubt that. O'Neill was pushing the use of lunar resources to build SPS. I think he was of the opinion that fusion was not going to make SPS obsolete in any foreseeable future. He did talk about harvesting lunar ice at the poles though, the existence of which was purely theoretical at the time. Having worked for two years at Forrestal and personally known G.K. O'Neill, the most charitable thing that anyone who worked there would say about him was that, quite fortunately, he didn't come to work very often! :-) Harry C. |
#26
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Mining the moon for unlimited Energy.
"Harry Conover" wrote in message
om... Having worked for two years at Forrestal and personally known G.K. O'Neill, the most charitable thing that anyone who worked there would say about him was that, quite fortunately, he didn't come to work very often! :-) What's Forrestal? I was only aware of his research/teaching career at Princeton, and his ultimately unsuccessful bid as an entrepreneur with Geostar. -- Regards, Mike Combs ---------------------------------------------------------------------- We should ask, critically and with appeal to the numbers, whether the best site for a growing advancing industrial society is Earth, the Moon, Mars, some other planet, or somewhere else entirely. Surprisingly, the answer will be inescapable - the best site is "somewhere else entirely." Gerard O'Neill - "The High Frontier" |
#27
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Mining the moon for unlimited Energy.
"Mike Combs" wrote in message ...
"Harry Conover" wrote in message om... Having worked for two years at Forrestal and personally known G.K. O'Neill, the most charitable thing that anyone who worked there would say about him was that, quite fortunately, he didn't come to work very often! :-) What's Forrestal? I was only aware of his research/teaching career at Princeton, and his ultimately unsuccessful bid as an entrepreneur with Geostar. It's the large government funded and Princeton University admisistered research center located off US Route 1 in Plainsboro, New Jersey just outside of Princeton. At the time that I worked there, circa 1969, it was host to the Princeton-Pennsylvania accelerator project, part of Project Matterhorn relating to the (then top secret) Lyman Spitzer Stellerator controlled fusion program, and an aeronautical research project that seem at that time to primarily focus on ground effects machines and hovercraft. For a brief history of Forrestal Research Center, see: http://www.princeton.edu/pr/pwb/02/0520/08a.shtml Jame Forrestal, for whom the research center was named, was a former secretary of defense who ended his too brief life via suicide. At least for a brief moment he, unlike most of us, 'soared with the eagles'. For a government bio on James Forrestal, see: http://www.defenselink.mil/specials/.../forrestal.htm Harry C. p.s. Back in 1969, I and some of my physicist/engineer friends at Forrestal became enamored with the romance, beauty, and emotional impact of shooting large, display fireworks. Many of the mortars that we employed to fire these 3 to 6" diameter devices were constructed in the machine shops at Forrestal, and welded by some of the finest heli-arc welding machines and skilled welders in existence at that time. We, often accompanied by the head of Princeton's Physics department, Dr. White (former director of Brookhaven labs), would often lauch these large fireworks from on top of the large, earthen shielding mound that covered the entire accelerator. Locals simply assumed that the lights and flashes in the sky were the result of 'atomic research' taking place in the facility. Gawd, if they had only known the facts we could have all, Dr. White included, landed up in the slammer! The strange lights in the sky above Forrestal gradually assumed the dimensions of an urban myth, and even became part of the 'patter' of local tour bus operators on passing by the facility. Evidently it was believe that our fireworks were the result of atomic bomb testing ongoing beneath the shielding mound! Fortunately, I left the area and went to work for Kodak in Rochester long before the sh*t hit the fan, if it ever did. |
#28
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Mining the moon for unlimited Energy.
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#29
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Mining the moon for unlimited Energy.
noodle doodle wrote: We also know how to beam energy over long distances. And how is that then??? Microwaves. But from the moon the transmitting antenna would be many kilometers across. I'd read that Japanese scientists have been working with lasers, you'd have to search google. I think efficiency is a tough nut there. But I would go with a chain and sprockets myself. Best, Dan. |
#30
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Mining the moon for unlimited Energy.
noodle doodle wrote:
We also know how to beam energy over long distances. And how is that then??? Microwave beam, rectifying antenna. Paul |
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